Fertilizer Use on Different Upland Cropping Systems for Soil Conservation in Yunnan
IPNI-1997-CHN-YN9
12 Jan 2005
2004 Annual Interpretive Summary
Sloping Land Management on Sustainable Agriculture in Yunnan, 2004
The nucleus of this sloping land management technology is the combination of balanced fertilization with alley cropping using different hedgerow cash crops. This technique is capable of achieving good profits for farmers and has been proven an effective means of protecting these landscapes from soil erosion and water losses. Originating in Sichuan, this technology has been transferred to other parts of China with similar landscapes. The objective of this project is to provide more supportive data and evidence for further extension nationwide.
Amounts of soil eroded were positively correlated with rainfalls from May to June when the corn stand was becoming established and the field was evolving from erosive bare soil to a protected, crop-covered state. There was no obvious relationship between rainfall and erosion after mid-July when the field was fully covered by the corn canopy. As a result, soil erosion was negatively correlated with total corn leaf area and root length. The soil loss in the treatment with contour cultivation, balanced fertilization, and hedgerow crops was lowered by 3.3 t/ha, a 89% reduction compared to farmers’ down-sloping cultivation, which typically lost 3.7 t/ha of soil annually. The loss of nitrogen (N), phosphorus (P) and potassium (K) through soil erosion was 30.7 kg N/ha, 19.2 kg P2O5/ha, and 534.2 kg K2O/ha for farmers' down-slope cultivation against 0.8 kg N/ha, 0.9 kg P2O5/ha, and 14.6 kg K2O/ha for contour cultivation plus balanced fertilizers and hedgerows. Thus, 97.4%, 95.3% and 97.3% less N, P, and K was removed from the system, respectively. In addition to the positive effect on soil erosion and nutrient loss, the cash crop hedgerows have formed firm bunds and now function as 'natural' terraces. Plant roots provide great soil stability and above ground portions prevent soil from washing down-slope. The alley croppig technique has prevented further gains in steepness of hillside slopes by an average of 0.750 (degrees) annually.
The net income for this improved practice was US$1,267/ha at Fuming. The integrated technology also increased soil moisture by 1 to 2% during the growing season, and helped protect crops against minor drought. Yunnan-09